In motorcycles, brake and clutch are manually actuated by a pump (“master cylinder”) actuated by a lever device mounted on the handlebar of the motorcycle itself, from which a hydraulic pipe extends to the system to be controlled, for example a brake.
The lever of the lever device is usually arranged along the handlebar grip and the motorcyclist, in order to actuate the lever itself, grips the handlebar along with the lever and closes his/her hand tight so as to turn the lever towards the grip itself. The lever movement produces a thrust that acts on a hydraulic piston, whose stroke or position determines the fluid pressure in said hydraulic pipe to control the brake or the clutch.
Since the various handlebars of motorcycles exhibit different shapes and also the motorcyclists' hands do not all have the same size, the need of being able to adjust the lever rest position relative to the handlebar grip is felt.
Several solutions for carrying out an adjustment of the lever position have been proposed. A group of these solutions provides for an adjustment device of the lever position, such as in U.S. Pat. No. 4,840,082.
This known device is provided with a lever that can rotate about a support shaft for pushing a stem that influences a piston for putting the brake fluid under pressure during the braking action.
The stem selectively couples with at least one seat of different depth of a rotating adjustment block, for varying the operating lever position relative to the handlebar.
Moreover, the lever can be rotated about a coupling shaft against the strength of a spring (“double fulcrum”), for releasing the stem from one of the seats and thus allowing the rotation of the rotating adjustment block by a gripping portion or knob obtained at an end of the rotating block and that raises transversally from the operating lever, or by a screwdriver that acts on a screw at the end of the block itself.
The stem thus slides on guiding grooves, until it couples with the desired seat; in this way, the relative position between lever and handlebar is adjusted.
However, this known device exhibits excessive overall dimensions in the cross direction relative to the adjustment lever, that is, axial to the rotating adjustment block.